Bow compass



June 17, 1947.

BOW COMPASS Filed Oct. 9. 1945 A. P. BARTUSCH Q 2,422,286

Patented June 17, 1947 UNITED STATES PATENT OFFICE BOW COMPASS Alexander P. Bartusch, Lockport, N. Y.

Application October 9, 1943, Serial No. 505,654

Claims. (Cl. 33-154 This invention relates generally to certain new and useful improvements in drafting instruments but more particularly to bow compasses or dividers for draftsmen, mechanics, toolmakers and the like.

One of the objects of the invention is to provide an instrument of this character which is so designed as to be simple, sturdy and inexpensive in construction, which is accurate in operation, and which is light in weight and easy to manipulate.

It has for a further object to provide a compass having a novel, sectional, stamped leg construction of maximum rigidity and one which is not subject to sidewise or lateral deflection, and wherein the sections of each leg are rigidly secured in predetermined spaced relation between the pivotal and adjustable bearing points.

'A still further object of the invention is to provide a drafting instrument having novel means for adjustably and detachably mounting the pivot or scribing point in a set position and for detachably securing thereto a pen or like attachment to the instrument. I

Other features of the invention reside in the construction and arrangement of parts hereinafter described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a front elevation of the compass embodying my invention. Figure 2 is an end view thereof. Figures 3 and 4 are enlarged transverse sections taken on the correspondinglynumbered lines in Figure 1. Figure 5 is a front elevation of a modified form of the invention. Figure 6 is an end View thereof. Figures 7 and 8 are enlarged transverse sections taken on the correspondingly-numbered lines in Figure 5. Figure 9 is a fragmentary side elevation of another modification of the invention.

Similar characters of reference indicate corresponding parts throughout the several views.

Referring to Figures L-4 inclusive of the drawings I0, I 0 indicate a pair of legs pivoted at their upper ends to a transverse pivot pin II for adjustment toward and from each other, each leg consisting of a pair of companion sections of relatively thin material disposed in transversely spaced relation and notched at their upper ends for engagement with correspondin annular grooves l2 formed in the pivot pin A substantially circular or loop-like spring 13 applied to the upper ends of the leg-sections serves to retain them on the pivot pin. These legs may be in the form of stampings and :intermediatetheir upper and lower ends each pair of sections is rigidly secured together against relative transverse displacement by a spacer member M which is provided with journals I5 resulting'in outwardly-facing shoulders 16 disposed to V abut against the opposing inner faces of the leg-sections, while their outer ends are upset or flanged, as indicated at I! over the outer faces of such sections. While those portions of the companion leg-sections between the pivot and spacer members II and M, respectively, are securely retained in parallel relation and against lateral deflection, the lower portions thereof below the spacer member are free to yield and to move toward and from each other to detachaloly receive therebetween a pivot or scribing point 18. As shown in Figure 2, these yieldable lower portions of the leg-sections converge somewhat immediately below the spacer member l4 and then continue downwardly in comparatively close parallel relation. On the inner faces of their terminal ends, these lower leg portions are provided with mating grooves l9between which the pivot 0r scribing point is arranged. 'A clamping screw 20 is employed for anchoring each point in its set position of adjustment in the companion'legn' As shown in Figure 1, the inner edges of the legs of the compass are bowed inwardly slightly below the axes of the spacer members and then outwardly at their lower ends, so that the pivot and scribing points are in their most efficient working position and can be brought closely together to accurately describe the smallest of circles. I 7

For the purpose of adjusting the compass legs toward and from each other an adjusting screw 2| is provided having a centrally-disposed actuating wheel 22, the opposite ends of the screw having right and left hand threads thereon engaging correspondingly threaded opening 23 formed in the spacer members I 4 which function as nuts for causing the legs to move toward and from each other in accordance with the turning of the actuating wheel in one direction or the other. While these spacer members retain the leg-sections rigidly in spaced relation and prevent their lateral or transverse deflection during the scribing operation or when pressure is imposed on the hand wheel during adjustment of the compass, sufficientclearance is provided to permit suchmembers to turn or swivel in response to the relative movements of the legs and the adjusting screw.

A finger-engagingstem 24 rises from the top of the compass centrally of its pivot pin ll, being secured at its lower end to the latter and passing a ruling pen. In this form of the invention, the

pivot point is supported between grooved clamp ing plates 21 disposed in the space provided by the lower ends of one of the sectional legs and adapted to be held in a set position by a clamping screw 28 passing transversely through the legsections and the plates. By this construction, the

pivot point 25 can be readily reversed without removing it from the compass, it being only necessary to loo'senthe clamping'screw suiilciently to enable the companion plates 21 to be turned as a unit about the axis of such screw;

In adapting the compass to the use of drafting tools, such'as the ruling pen 26, one of the sectional legs is shortened, as indicated at 29, and thetool has a coupling head or tongue 30 at its upper end for part-way lateral insertion in the space provided by the shortened leg, A clamping screw 3| passing through a threaded opening in the tongue and abutting at its headed end against the outer edges of the leg-sections serves to detachably retain the tool in its operative position.

As shownin Figure 8, the shank 32 of the tool,

from'whichthetongue 30 extends in a lateral direction, has outwardly-diverging shoulders 33 thereon at its junction with the tongue which abutagainst like beveled edges 34-f0rmed on the adjoining portions of the leg-sections, whereby to securely clamp the parts in firm wedge-like engagement. yv

Asshown in -'gure;9,'the ruling penr35 may be adjustably pivoted at '36 in the space between the foreshortened end-sections 31 0f one of the compass-legs. 1 7

I claim as my invention: 1

a -1. A compass of the character described, comprising a pair'of legs pivoted at their upper ends for adjustment toward and from each other, each of-said legs consisting of a pair of companion sections disposed in transversely spaced relation from their upper pivoted ends to the lower free ends thereof and adapted to receive in operative relation at such lower ends a pivot or scribing point, an adjusting screw spanning said legs for effecting their adjustment, and a combination spacer and nutmember disposed between coming to retain the respective leg-sections in rigid panion leg-sections intermediate their upper and lower ends for retaining them in fixed spaced relationand for operatively receiving the oppo site ends of the adjusting screw, those portions of the legs below the retaining member being free to spring toward and from each other.

, 2. A. compass of the character described, comprising apair of legs pivoted at their upper ends for adjustment toward and from each other, each of said legs consisting of a pair of companion sections disposed in transversely spaced relation from their upper pivoted ends to the lower free ends thereof, an adjusting screw spanning said legs for effecting theiradjustmenta combination spacer and nut member joined at its opposite ends to the companion leg-sections intermediate the upper and lower ends thereof for retaining them in fixed spaced relation in the axial plane of the adjusting screw pivot of the legs, the leg-sections below said spacer and nut member being relatively free, and a clamping element applied to the lower extremities of the leg-sections for removably clamping a pivot or scribing point thereto.

3. A compass of the character described, comprising a pair of legs pivoted at their upper ends for adjustment toward and from each other, each of said legs consisting of a pair of companion sections disposed in transversely spaced relation from their upper pivoted ends to the lower free ends thereof, annularly-grooved members in supporting and space-governing relation to the companion sections of each'leg, one of said members being disposed at the upper end of the legs and constituting the common pivot therefor and theother members being rotatably disposed below such pivot in parallel relation thereto and servspaced relation at a point intermediate their upper and lower ends, an adjusting screw spanning said legs and 'operatively connected at its ends to the companion lower leg-section retaining members,- those portions of, the leg-sections below the retaining members being free to yield and'to relatively move toward and from each other, and clamping elements applied to the lower ends of such'leg-sect-ions for removably clamping a pivot or scribing point thereto.

4: A compass of the character described, comprising a pair of legs pivoted at their upper ends for adjustment toward and from each other, each of said legs consisting, of a pair of companion sections disposed in transversely spaced relation .from their upper pivoted ends to the lower free ends thereof, a. pivot member in supporting andspace-governing relation to the upper ends of the companion sections of said pair of legs, a spacer member disposed between the companion sections of each leg at a point intermediate the upper and lower ends thereon-said spacer member being free to turn about an axis parallel to the pivot member and flanged. at itsv opposite ends over said leg-sections to retain them in'fixed spaced relation, those portions of the leg-sections below the; retaining spacer member being contracted in parallel spaced relation and free to spring toward and from each other, and clamping elements applied to the lower ends of the leg-sections for removably clamping a pivot or scribing point thereto.

5. ma compass of the character'described, a leg therefor consisting of a pair of companion sections disposed in transversely-spaced, parallel I UNITED STATES PATENTS I Number Name Date 7 2,297,999 Eubanks Oct. 6,1942 1,68 0,194 V Akashi .L Q Aug. '7, 1928 V FOREIGN PATENTS 7 Number Country Date 91,064 Germany Sept. 8; 1895 

